Hand-operated reciprocating pump

ABSTRACT

A reciprocating pump includes a cylinder; a piston including apertures and an annular bottom flange; a first check valve secured to a piston rod and including an annular groove; a coupling at cylinder bottom; a sealing ring sandwiched between the cylinder bottom and the coupling; a second check valve engaged with the ring and including tunnels and a bottom socket; and a metal block fitted in the socket. Pushing a handle upward will move the piston rod downward to sealingly engage the flange with the groove, remove air from the cylinder, and block the coupling by both the socket and the block. Pushing the handle downward will move the piston rod upward to disengage the flange with the groove, open the second check valve, suck fluid into the cylinder through the coupling, the tunnels, and the apertures, and discharge the fluid.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to pumps and more particularly to a single-acting type hand-operated reciprocating pump with improved characteristics.

2. Related Art

A conventional hand-operated reciprocating pump is shown in FIGS. 1, 1A, 1B, and 2. The pump comprises a cylinder 1. Within an upper portion of the cylinder 1 there are provided an upper piston R including a piston head R1, a plurality of apertures R11 through the piston head R1, and a piston rod 12 having a lower portion 121, a lower first check valve A provided below the piston R and including a disc A1 having a plurality of apertures A11, and a screw S threadedly secured to both bottoms of the lower portion 121 and the first check valve A. Within a lower portion of the cylinder 1 there are provided a lower second check valve A2 including a plurality of apertures A21, an intermediate circular seal R2 including a plurality of apertures R21, and an upper valve A3. All of these three components are secured and laminated together by a fastener. On an outer surface of the lower end of the cylinder 1 there is provided a hollow, staged coupling 13 having inner threads 131 threadedly secured to the lower end of the cylinder 1.

However, the prior art suffered from a couple of disadvantages. For example, a first gap H1 exists between the piston R (i.e., piston head R1) and the first check valve A. This will not completely remove air from the cylinder 1 (i.e., upper chamber 11) during a piston upstroke since air may enter the upper chamber 11 from a lower chamber of the cylinder 1 through the apertures A11 and R11 as indicated by arrows. This is because the piston R does not completely adhere to the first check valve A. Further, a second gap H2 exists between the valve A3 and the seal R2. This will not completely block fluid W from entering the lower chamber during a piston downstroke since fluid W may enter the lower chamber from a reservoir (not shown) through a suction pipe (not shown) and the apertures A21 and R21 as indicated by arrows. This is because the valve A3 does not completely adhere to the seal R2. As a result, less amount of fluid W is discharged. Thus, the need for improvement still exists.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a reciprocating pump comprising a cylinder including a spout; a piston slidably provided in the cylinder and including a piston rod extended through beyond a top of the cylinder, a plurality of apertures, and an annular bottom flange; a moveable first check valve secured to a lower end of the piston rod and including a plurality of cavities provided on its top, and an annular groove provided along its peripheral edge; a handle including a front end pivotably connected to a top end of the piston rod, and a plurality of pivots, and a link having a lower end pivotably connected to the cylinder and an upper end releasably, pivotably connected to one of the pivots; a hollow, staged coupling provided at a bottom end of the cylinder; a sealing ring sandwiched between the bottom end of the cylinder and the coupling; a second check valve including a top surface engaged with the sealing ring, a plurality of peripheral tunnels, a cylindrical socket extended downward from a central part of its bottom, and an annular trough provided between the socket and the tunnels; and a metal block fitted in the socket; wherein in response to pushing the handle upward, the piston rod moves downward in the cylinder to sealingly engage the flange with the groove, remove air from the cylinder, and block the coupling by both the socket and the block; and in response to pushing the handle downward as an immediately next stroke of the piston, the piston rod moves upward in the cylinder to disengage the flange with the groove, disengage the second check valve with the coupling, suck fluid from a reservoir into an upper portion of the cylinder through the coupling, the tunnels, a gap between the first check valve and the piston, and the apertures, and discharge the fluid out of the spout from the upper portion of the cylinder.

In one aspect of the present invention the cylinder further comprises a projected joint pivotably connected to the lower end of the link.

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of the cylinder of a conventional hand-operated reciprocating pump;

FIG. 1A is a detailed view of the area indicated by an arrow in FIG. 1;

FIG. 1B is a detailed view of the area indicated by another arrow in FIG. 1;

FIG. 2 is a perspective view of the pump in FIG. 1;

FIG. 3 is an exploded view of a preferred embodiment of hand-operated reciprocating pump according to the invention;

FIG. 4 is a perspective view of the pump in FIG. 3;

FIG. 5 is a longitudinal sectional view of the pump in FIG. 3 showing a pumping operation thereof;

FIG. 6A is an enlarged view of the piston in FIG. 5; and

FIG. 6B is an enlarged view of a lower end of the cylinder in FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 3 to 6B, a hand-operated reciprocating pump in accordance with a preferred embodiment of the invention comprises a cylinder 2 including a spout 24, a projected joint 25, and a chamber 21; a piston 3 slidably provided in the cylinder 2 and including a central bore 33, a piston rod 22 extended through the bore 33 and beyond a top of the cylinder 2, a plurality of equally spaced apertures 31, and an annular flange 32 extended downward from a bottom of the piston 3; a moveable first check valve 4 provided on a lower end of the piston rod 22 and fastened by a screw S, the first check valve 4 including a plurality of equally spaced cavities 41 provided around its top surface, an annular groove 42 along its peripheral edge, and a central bore 43 with the piston rod 22 extended through; and a handle 9 including a front end pivotably connected to a top end of the piston rod 22, a rear end formed as a hand grasping portion 92, an intermediate pivot section 91 having a plurality of pivots 911 (three are shown), and a link 93 having a lower end pivotably connected to the joint 25 and an upper end pivotably connected to one of the pivots 911.

On an outer surface of the lower end of the cylinder 2 there is provided a hollow, staged coupling 7 including inner threads 71 threadedly secured to the lower threaded end of the cylinder 2, a central channel 72 in fluid communication with a suction pipe (not shown), and an annular trough 73. Within a lower portion of the cylinder 2 there are provided a sealing ring 5 having its edge tightly pressed between a bottom end of the cylinder 2 and a shoulder of the coupling 7; a second check valve 6 provided between the ring 5 and the coupling 7 and including a flat top surface engaged with the ring 5, a plurality of peripheral tunnels 61, a cylindrical socket 62 extended downward from a central part of its bottom, and an annular groove 63 provided between the socket 62 and the tunnels 71; and a metal block 8 fitted in the socket 62.

A user may decide to connect the link 93 to one of the pivots 91 for the purposes of labor saving, time saving, etc. During a piston downstroke by pushing the handle 9 upward, the piston rod 22 moves downward in the cylinder 2 to sealingly engage the flange 32 with the groove 42. As such, air in the chamber is completely removed (i.e., vacuum). Also, the channel 72 is blocked by the closed second check valve 6 since the socket 62 falls into the channel 72 due to weight of the block 8 and blocks same (see FIG. 6B). Alternatively, during a piston upstroke by pushing the handle 9 downward, the piston rod 22 moves upward in the cylinder 2 to disengage the flange 32 with the groove 42 due to vacuum in the chamber 21. Also, the second check valve 6 disengages with the coupling 7 (i.e., the second check valve 6 is open and the channel 72 is not blocked). As such, fluid W is sucked from a reservoir (not shown) into a lower portion of the chamber 21 through the channel 72 and the tunnels 61. Further, fluid W passes the a gap between the first check valve 4 and the piston 3 and enters an upper portion of the chamber 21 through the gap and the apertures 31. Finally, fluid W is discharged out of the spout 24 from the upper portion of the chamber 21.

While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims. 

1. A reciprocating pump comprising: a cylinder including a spout; a piston slidably provided in the cylinder and including a piston rod extended through beyond a top of the cylinder, a plurality of apertures, and an annular bottom flange; a moveable first check valve secured to a lower end of the piston rod and including a plurality of cavities provided on its top, and an annular groove provided along its peripheral edge; a handle including a front end pivotably connected to a top end of the piston rod, and a plurality of pivots, and a link having a lower end pivotably connected to the cylinder and an upper end releasably, pivotably connected to one of the pivots; a hollow, staged coupling provided at a bottom end of the cylinder; a sealing ring sandwiched between the bottom end of the cylinder and the coupling; a second check valve including a top surface engaged with the sealing ring, a plurality of peripheral tunnels, a cylindrical socket extended downward from a central part of its bottom, and an annular trough provided between the socket and the tunnels; and a metal block fitted in the socket; wherein in response to pushing the handle upward, the piston rod moves downward in the cylinder to sealingly engage the flange with the groove, remove air from the cylinder, and block the coupling by both the socket and the block; and in response to pushing the handle downward as an immediately next stroke of the piston, the piston rod moves upward in the cylinder to disengage the flange with the groove, disengage the second check valve with the coupling, suck fluid from a reservoir into an upper portion of the cylinder through the coupling, the tunnels, a gap between the first check valve and the piston, and the apertures, and discharge the fluid out of the spout from the upper portion of the cylinder.
 2. The reciprocating pump of claim 1, wherein the cylinder further comprises a projected joint pivotably connected to the lower end of the link. 